This invention relates to metal hose assemblies for conveying low- to medium-pressure fluids. More particularly, it relates to end fittings for flexible metal hoses used to carry refrigerants or coolants.
Flexible metal hoses typically have an innercore or convoluted tube made of copper, brass, bronze, steel or the like. The innercore has fluted convolutions, which render it readily flexible in axial planes. The core is covered with a reinforcing layer of braided metal wire to protect the assembly from injury upon contact with other objects, to prevent foreign matter from becoming lodged between the convolutions, and to improve its pressure capability and appearance. An optional plastic jacket is sometimes used over the braid for added abrasion protection, ease in cleaning, and/or appearance (permits color and labelling).
Both ends of the hose have attached fittings to removably connect the assembly to fluid reservoirs, machines or lines. The attachment of such fittings has often been accomplished by soldering and brazing. For those processes, the fitting usually has a cup-shaped cavity to receive an end of the hose; and solder or braze material is deposited in the cup to form a bond between the fitting and the hose when the fitting is inserted in the cavity. Certain difficulties occur in soldering such a fitting to the end of a flexible metal hose. When the flexible hose is initially cut to size, the wire braid tends to unravel and expand at the severed end, rendering the hose exceedingly difficult to insert in the cavity of a fitting. Sometimes, the braid is pushed back during insertion of the fitting such that no bond (or an inadequate bond) is formed between the fitting and the braid. It is therefore necessary to squeeze and hold the braid together prior to such insertions, presenting considerable inconvenience and causing loss of time in the manipulation.
Welding, as opposed to soldering, is sometimes used to attach end fittings to flexible hose assemblies. It provides a quick attachment, especially with modern techniques such as computerized electric-arc welding. The end fitting, however, has to be machined or sized to achieve the geometry required to make a stable welded connection to the metal innercore. This machining drives up assembly costs.
It is, therefore, the primary object of the present invention to provide a unique end fitting, for flexible metal hose assemblies, which overcomes the deficiencies of the prior art.
It is a general object to provide a flexible metal hose assembly wherein a unique metal fitting is firmly secured by welding and crimping, but without machining the fitting beforehand.
It is another object to produce such a fitting at low cost and high speed of manufacture, as compared to the machined end fittings traditionally used.